The use of ribbon-like strips of flexible resilient elastomeric or similar deformable material to seal the closure gaps between refrigerator doors and cabinets, or the like, is well-known. The strips are applied marginally, either directly or with the aid of a track, on one or both of the facing surfaces of the door perimeter or abutting shoulder of the cabinet frame. The gasket profile is filled out with a magnetic strip or elastically compressible sponge or other filler to ensure that the gap between the shoulder and frame is filled.
Door gaskets for commercial and home refrigerators come in many different profiles, each model refrigerator typically having its own separate original equipment gasket configuration. To replace a gasket, therefore, it has heretofore been necessary for the service technician to either maintain a large gasket inventory, or suffer delay until a matching gasket can be obtained. Some gaskets include a base or tail that has a dart-like projection which is inserted into a slot. Others have a "C-shaped" tail or flange that goes under an edge of a door skin or liner, necessitating the removal of the liner for replacement. The gap between a door and frame is filled by the gasket, sometimes having a magnetic strip attached atop a bellows which expands to fill the gap. Other times, the gap is filled by a compression gasket that has an expanded, compressible contour. Examples of prior art gasket configurations are given in U.S. Pat. Nos. 3,111,728; 3,126,590; 3,562,957; 4,441,278; 4,644,698; 4,700,509; and 4,860,495.
Applicant herein has developed a new closure sealing system, especially suited to refrigerator door closures, that utilizes a universal replacement gasket and track system. Old "C-shaped" gaskets that have a tail embedded under a door skin can be cut off. Other old gaskets can be removed. Both are replaced by a single U-shaped guide channel that can be screwed, stapled or glued to the frame or door, and into which a universal gasket can be fitted. The gasket is of a resilient elastomeric material and includes an upper magnet cavity portion, an intermediate expandable, hollow bellows portion and a base portion. The bellows is attached centrally at the top of the base, and the magnet cavity is attached centrally at the top of the bellows. The base comprises equal, opposite outwardly extending flanges formed to be captured beneath corresponding inwardly-turned upper free edges of the guide channel. The magnet cavity is dimensioned to receive a magnetic strip or compressible sponge insert therein. The bellows can be left empty, or filled with a sponge or other compressible filler. Using Applicant's system, once the track has been installed, the universal gasket will fit as a replacement for all other gaskets. The gasket can be used either with or without the magnetic strip, and with or without one or more sponge fillers, so as to meet all gap requirements.
Whether a traditional gasket strip is employed, or Applicant's new universal replacement gasket and track system is used, there is a need to economically and conveniently join angled ends of gasket strips together at corners. The present invention provides a heat welding apparatus and method suitable to accomplish such purpose.